If you win any outside scholarships, does the awarded amount just detract from your financial aid packet? If then, wouldn’t there be no need to actually apply for scholarships?
Your FA from Harvard will have a term-time job expectation and a summer earnings expectation. Outside awards will first be applied to reduce the term time job, then the summer earnings expectation. Outside awards exceeding that amount would reduce your FA from Harvard.
Harvard’s financial aid site has an explanation of outside scholarships.